Estoque de carbono em Latossolos com diferentes usos na região do Triângulo Mineiro, MG

Abstract

The aim of this study was to evaluate the effect of land use in different management systems in the rural region of Uberlândia-MG on C stocks (EstC). Five different uses of soils of the same pedogenetic class, Oxisoils, were considered: 1. Native Cerrado; 2. Area with grain cultivation in a no-till system; 3. Native vegetation in hydromorphic soils - Vereda; 4. Oxisoils with grain in a conventional cultivation system; 5. Oxisoils with various crops in an irrigated area (pivot). The treatments were arranged in a 5 x 7 factorial scheme, with five cropping systems and seven depths, and distributed in a completely casualized design with four replications. In each cropping system, four 60 cm deep trenches were opened to collect soil samples from the different layers: 0-5, 5 - 10, 10 - 20, 20 - 30, 30 - 40, 40 - 50 and 50 - 60 cm. In addition to the deformed samples, undeformed samples were taken to determine the apparent density of the soil and calculate the EstC. These samples were taken at three depths: 0-20, 20-40 and 40-60 cm. The soil's total organic carbon content (TOC) was obtained by wet digestion of the samples with Na dichromate and measured by spectrophotometry. The data was subjected to analysis of variance to verify the effect of the management systems (p ≤ 0.05), with the averages being compared to the mean values. As expected, the hydromorphic soil samples estimated carbon outputs were bigger than all the other cultivated systems, mainly in the 40-60 cm range. The COT values were higher at the depths closer to the surface, and didn’t differentiate statically between areas of native Cerrado and the other systems.